This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Micronutrient malnutrition is one of major health problems in the world, especially in developing countries. Zinc (Zn) malnutrition in children accounted for 35% in the world, and over 50% in China. Micronutrient deficiencies in human mainly resulted from low concentration and availability of micronutrients in diets. Understanding physiology and molecular physiology of Zn dense in rice grain is of great importance for Zn biofortification in soil-plant system for better human health. In the past more research has been focused on Zn acquisition from soils under deficient stresses, but less is done on the mechanisms of Zn transport and dense into rice grain. It is suggested that Zn transport in plant is regulated by some ZIP transporter genes, and Zn accumulation in grain is associated with some organic ligands like AA and ferritin. However, little information is available on the in vivo Zn localization or complexation in grains, which are the major regulator for Zn bioavailability in rice grain. The objectives of this proposed research are: 1) to determine the dynamic of cellular distribution of Zn in grain of dense rice mutant and low phytate mutant during developing stages using SRXRF technique;2) to characterize the major binding forms of Zn in grains of both Zn-dense and low-phytate mutants using XAS techniques;Our groups has been working on Zn efficiency in rice and Zn hyperaccumulation in Sedum alfredii for many years, and has a good research foundation, including the novel plant materials (Zn dense grain mutant and low phytate mutant rice), and previous experience of SRXRF and XAS techniques.